Heated Seats Description and Operation

[Rusty2009]

Symptoms - Seat Heating and Cooling

Note: The following steps must be completed before using the symptom tables.

1. When diagnosing a heated seat system condition perform the Diagnostic System Check - Vehicle , before using the symptom tables in order to verify that all of the following are true:

•  There are no DTCs set.

•  The control module(s) can communicate via the serial data link.

2. Review the system operation in order to familiarize yourself with the system functions. Refer to Heated Seats Description and Operation


Visual/Physical Inspection

• Inspect for aftermarket devices which could affect the operation of the power seats. Refer to Checking Aftermarket Accessories.

• Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

• Inspect the seat adjuster track for conditions which may cause binding or objects within the seat adjustment range which obstruct movement or interfere with wiring.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections.

Symptom List

Refer to the Front Heated Seat Malfunction diagnostic procedure in order to diagnose the symptom.

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Front Heated Seat Malfunction

Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

[TR] [TD]Circuit[/TD] [TD]Short to Ground[/TD] [TD]Open/High Resistance[/TD] [TD]Short to Voltage[/TD] [TD]Signal Performance[/TD] [/TR] [TR] [TD]Driver Heated Seat Element Control Terminal 3 X2[/TD] [TD]B242A 02[/TD] [TD]B2425 0D[/TD] [TD]B242A 01[/TD] [TD]B2425 0B, B2425 0E[/TD] [/TR] [TR] [TD]Driver Heated Seat Element Control Terminal 1 X2[/TD] [TD]B242A 02[/TD] [TD]B2425 0D[/TD] [TD]B242A 01[/TD] [TD]B2425 0B, B2425 0E[/TD] [/TR] [TR] [TD]Driver Heated Seat Cushion Temperature Sensor Signal[/TD] [TD]B1925 02[/TD] [TD]B1925 05[/TD] [TD]B1925 05[/TD] [TD]B2345 13[/TD] [/TR] [TR] [TD]Driver Heated Seat Cushion Temperature Sensor Low Reference[/TD] [TD]--[/TD] [TD]B1925 05[/TD] [TD]--[/TD] [TD]B2345 13[/TD] [/TR] [TR] [TD]Passenger Heated Seat Element Control Terminal 5 X2[/TD] [TD]B242A 02[/TD] [TD]B2430 0D[/TD] [TD]B242A 01[/TD] [TD]B2430 0B, B2430 0E[/TD] [/TR] [TR] [TD]Passenger Heated Seat Element Control Terminal 2 X2[/TD] [TD]B242A 02[/TD] [TD]B2430 0D[/TD] [TD]B242A 01[/TD] [TD]B2430 0B, B2430 0E[/TD] [/TR] [TR] [TD]Passenger Heated Seat Cushion Temperature Sensor Signal[/TD] [TD]B2170 02[/TD] [TD]B2170 05[/TD] [TD]B2170 05[/TD] [TD]B2345 13[/TD] [/TR] [TR] [TD]Passenger Heated Seat Cushion Temperature Sensor Low Reference[/TD] [TD]--[/TD] [TD]B2170 05[/TD] [TD]--[/TD] [TD]B2345 13[/TD] [/TR]

Circuit/System Description

The driver and passenger heated seats are controlled by separate heated seat switches that are located in the HVAC control. When a heated seat switch is pressed, a serial data message is sent from the HVAC control to the HVAC control module indicating the heated seat command. The HVAC control module serves as a gateway to transmit the message to the heated seat control module via the serial data line. In response to this message, the seat heating control module applies battery positive voltage through the element supply voltage circuit to the appropriate seat heating elements. The seat heating control module then sends a serial data message back to the HVAC control module to gateway the information to the HVAC control to either illuminate or turn off the appropriate temperature indicator.

Reference Information

Schematic Reference

Heated/Cooled Seat Schematics
Connector End View Reference

Component Connector End Views
Description and Operation

Heated Seats Description and Operation
Electrical Information Reference

• Circuit Testing

• Connector Repairs

• Testing for Intermittent Conditions and Poor Connections

• Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1.Engine ON, observe the scan tool Driver Seat Heating/Venting/Cooling Mode parameter while pressing the driver HEATED seat switch. The reading should change between Off and Back & Cushion Heat.
⇒ If not the specified value, replace the A26 HVAC control.

2.Observe the scan tool Passenger Seat Heating/Venting/Cooling Mode parameter while pressing the passenger HEATED seat switch. The reading should change between Off and Back & Cushion Heat.
⇒ If not the specified value, replace the A26 HVAC control.

3.If all scan tool parameter readings are normal, there are no DTCs set, and the driver and/or passenger heated seat is inoperative, replace the K29 seat heating control module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• Heater and Air Conditioning Control Replacement

• Control Module References for seat heating control module replacement, setup, and programming